In the field of advertising, the sides of trucks may be used to display advertising signs. Such mobile advertisements benefit advertisers with a useful advertising medium, and further benefit truck operators with an additional revenue source.
Advertising signs typically comprise printed PVC (poly vinyl chloride) sheets that are impervious to air and water. The sign may optionally further comprise reinforcements and fasteners.
Advertising signs on vehicles need to be prevented from catching air as the vehicle moves. The flow of air behind the sign can cause billowing, flapping and damage to or loosening of the sign.
One solution uses PVC sheets that are tensioned into a frame attached to the side of the truck. A PVC sheet, that has been digitally printed with an image, is unrolled and beading is fed into ridges around the edge of the sheet. The edge now containing the beading is fed into grooves along a frame attached to the side of the truck, and finally the sheet with beading is riveted securely into the frame.
U.S. Pat. No. 6,305,111 discloses an advertising display mounted on the side of a truck or any other substantially planar surface. The display includes an elastic display sign with four edges reinforced by stays. Attachment fittings are spaced along the edge of the supporting structure.
U.S. Pat. No. 6,167,649 discloses an information display system mounted on flat surfaces, such as the side of truck trailers, including a frame with a flexible sheet attached to the frame. There is an anchoring bracket rigidly attached to the side wall at each corner. Other anchoring brackets are attached at various locations along the sign's edges. The sign is a sheet of flexible plastic or cloth made from tightly woven natural or synthetic fibres.
The problems with these known approaches are the complicated and obtrusive nature of the fasteners attached (including by bolting) to the body of the vehicle. Furthermore, the advertising sheet itself requires complex adapting or attachment to a frame. All of these approaches use complex methods of engaging and tensioning the sheet.
Using a mesh sheet to allow more free airflow through the sign has the disadvantages of being difficult to print, having reduced quality of the printed image, being difficult to clean, having a tendency to stretch and the inability to add hidden fasteners around the centre of the image.